Electronic device with connecting structure

ABSTRACT

A semiconductor device including a connecting structure includes an edge region, a first trench and a second trench running toward the edge region, a first electrode within the first trench, and a second electrode within the second trench, the first and second electrodes being arranged in a same electrode plane with regard to a main surface of a substrate of the electronic device within the trenches, and the first electrode extending, at an edge region side end of the first trench, farther toward the edge region than the second electrode extends, at an edge region side end of the second trench, toward the edge region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Divisional Patent Application claims priority to U. S. patentapplication Ser. No. 11/947,552, filed on Nov. 29, 2007, which claimspriority to German Patent Application No. 10 2006 056 809.5, which wasfiled on Dec. 1, 2006, and are incorporated herein in its entirety byreference.

BACKGROUND

One aspect relates to a connecting structure for an electronic device,and to a connecting structure for a semiconductor device including atrench structure, such as a vertical trench field-effect transistor, ortrench-gate transistor, a trench capacitor, or trench capacitance, or aDMOS (double diffused metal oxide semiconductor) power transistorcomprising a respective trench structure.

In many modern devices, including semiconductor devices, theconstruction space available for a specific device is a set constraintin the context of developing such devices. Especially with smallsemiconductor devices having typical chip edge lengths of 2 mm and less,the surface area which has to be provided for contacting the finisheddevice represents a substantial proportion of the overall surface areaof the device. In this context, bondpads frequently need to include asurface area of up to 500 μm×500 μm, for example to enable, in thecontext of a common bond processing step, contacting between therespective bondpad and the housing via more than one bondwire, orcontact wire.

Even in the case of other contacting methods, for example by means ofpressing contacts or resilient pins, the respective contacting areacannot be designed to be significantly smaller. If, typically, forexample, three bondwires having diameters of 50 to 100 μm in each caseare used per bondpad, the respective bondpad may hardly be designed tobe smaller than 300 μm×300 μm. Also, there are conductor-line structureson the semiconductor device which are for electrically contacting thesemiconducting structures and cells. In the context of development, thesurface area necessary for this is not available, or is available onlyto a highly limited extent, for the actual cell structure of thesemiconducting device.

The connecting structures for operation thus considerably restrict thesurface area available for the cell structure of the semiconductingdevice. With regard to the overall surface area of the device, the spacerequirements of the contacting connecting structures considerably reducethe possible space requirements or the possible surface area for theactive regions. The construction space necessary for contacting thusconsiderably restricts the efficient further development of the devices.

When developing new generations of DMOS power transistors, an importantgoal is the reduction of the specific on-resistance R_(on)·A, forexample.

A reduction of the specific on-resistance is desirable for the veryreason alone that it may minimize the static power loss, on the onehand, and that higher current densities may be achieved, on the otherhand, as a result of which smaller and cheaper chips may be employed forthe same total current.

SUMMARY

In accordance with one embodiment, a connecting structure for anelectronic device includes an edge region of the device, a first trenchand a second trench running toward the edge region, a first electrodewithin the first trench, and a second electrode within the secondtrench, the first and second electrodes being arranged in a sameelectrode plane with regard to a main surface of a substrate of theelectronic device within the trenches, the first electrode extending, atan edge region side end of the first trench, farther toward the edgeregion than the second electrode extends, at an edge region side end ofthe second trench, toward the edge region, and the first electrode beingconnected to a connection structure for a first potential, and thesecond electrode being connected to a connection structure for a secondpotential.

In accordance with a further embodiment, a connecting structure for anelectronic device includes a first edge region, a second edge regionopposite the first edge region, a central region arranged between thefirst edge region and the second edge region, first, second, and thirdtrenches running toward the first edge region and the second edgeregion, and a first electrode within the first trench, a secondelectrode within the second trench, and a third electrode within thethird trench in an electrode plane arranged with regard to a mainsurface of a substrate of the electronic device, the first electrodeextending farther into the first edge region than the second and thirdelectrodes, the third electrode extending farther into the second edgeregion than the first and second electrodes; the first and thirdelectrodes not extending into the central region, the first electrodeand the third electrode being arranged on a straight connecting line,the second electrode being arranged offset to the connecting line, andthe first electrode and the third electrode being contacted with aconnection structure for a first potential, and the second electrodebeing connected with a connection structure for a second potential.

In accordance with a further embodiment, a connecting structure for anelectronic device includes an edge region of the device, a first trenchand a second trench running toward the edge region, a first electrodewithin the first trench, no further electrode being arranged, to theside of the first electrode, within the first trench, a second electrodewithin the second trench, no further electrode being arranged, to theside of the second electrode, within the second trench, the firstelectrode, in an edge region side end of the first trench, extendingfarther toward the edge region than the second electrode at an edgeregion side end of the second trench extends towards the edge region,and the first electrode being connected to a connection structure for afirst potential, and the second electrode being connected to aconnection structure for a second potential.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIG. 1 illustrates a top view of an electronic device comprising anembodiment of an inventive connecting structure;

FIGS. 2 a-2 c illustrate three partial cross-sectional representationsof the electronic device illustrated in FIG. 1;

FIG. 3 illustrates a top view of an electronic device comprising asecond embodiment of a connecting structure;

FIG. 4 illustrates a partial cross-sectional representation of theelectronic device illustrated in FIG. 3;

FIG. 5 illustrates a top view of a further electronic device comprisinga third embodiment of a connecting structure;

FIG. 6 illustrates an enlargement of a detail of the top viewillustrated in FIG. 5;

FIGS. 7 a-7 c illustrate three partial cross-sectional representationsof the electronic device of FIG. 5 in the detail illustrated in FIG. 6;

FIG. 8 illustrates a further enlargement of a detail of the top viewillustrated in FIG. 5; and

FIGS. 9 a-9 b illustrate two partial cross-sectional drawings of theelectronic device of FIG. 5 in the detail illustrated in FIG. 8.

DETAILED DESCRIPTION

In the following Detailed Description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is used withreference to the orientation of the Figure(s) being described. Becausecomponents of embodiments can be positioned in a number of differentorientations, the directional terminology is used for purposes ofillustration and is in no way limiting. It is to be understood thatother embodiments may be utilized and structural or logical changes maybe made without departing from the scope of the present invention. Thefollowing detailed description, therefore, is not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims.

It is to be understood that the features of the various exemplaryembodiments described herein may be combined with each other, unlessspecifically noted otherwise.

A first embodiment will be explained in more detail with reference toFIGS. 1 to 9 b in the form of a connecting structure for an electronicdevice, and the electronic device itself will be explained below in moredetail with reference to the representations depicted in FIGS. 1, 2 a, 2b, and 2 c.

To simplify the representation, a representation of those elements ofthe electronic device in question which are of secondary importance forthe embodiments of the connecting structure concerned has beenspecifically dispensed with. For example, the partial cross-sectionaldrawings of FIGS. 2 a, 2 b, and 2 c do not contain a representation ofdoping profiles or other structures not related to the actual connectingstructure, so as to keep the representation simple and clear. If theelectronic device, for which an embodiment of the connecting structureis illustrated, is a vertical transistor, for example, the associateddoping will not be contained in the figures in the region between thetrenches, the so-called mesas. If the electronic device is acapacitance, for example, an electric conductivity may be introduced, inthe region of the mesas, by means of a specific implantation by means ofdonors or acceptors which belong to a doping of the region in question,so as to reduce, for example, a typical RC time of the resultingcapacitor. This implantation is also not illustrated here.

In addition, the structures depicted in FIGS. 1, 2 a, 2 b, and 2 c maybe prepared, or manufactured, by common methods of semiconductortechnology and thin-film technology. These include, among others, thedeposition of epitactic layers by means of sputtering processes, CVDprocesses (chemical vapor deposition), or other physical and/or chemicaldeposition processes. The common semiconductor process steps andthin-film process steps further include the deposition ofpolycrystalline or amorphous semiconducting, insulating or metalliclayers by means of sputtering processes, CVD processes, vaporizationprocesses, or other chemical and/or physical deposition processes, bymeans of which polymorphous silicon layers (poly Si), for example, maybe deposited. Examples of a deposition of silicon dioxide (SiO₂) bymeans of a CVD process are the so-called TEOS process (tetraethylorthosilicates). Here, metal layers may include, for example, layersmade of one or several alloys and/or metals.

The further thin-film and semiconductor process steps further includestructuring steps by means of photolithography or other masks along withphysical and/or chemical etching steps as well as process steps forremoving the mask. The etching steps include, for example, thewet-chemical etching process, physical etching processes (IBE=ion beametching) and physical/chemical etching processes (RIE=reactive ion beametching). Specifically, IBE processes and RIE processes are alsoreferred to as plasma etching processes. The common processes forremoving a mask include, among others, wet-chemical processes, such asexposing the intermediate result to an acetone solution, or incinerationby means of an oxygen plasma or a different plasma on the basis of areactive gas or gas mixture.

Further common processes further include steps of oxidizingsemiconducting or metal layers and structures, tempering steps orannealing steps by exposing the intermediate result to an increasedtemperature, possibly by exposure to a specific atmosphere, steps ofimplanting to achieve a doping, or a doping profile, diffusion steps,formation of further compounds (for example, titanium silicides),implantations for forming contact regions, depositing complex compounds(for example, AlSiCu), lift-off processes and further standard processesfor processing a rear of the substrate of the (to-be) electronic device.Similarly, planarization steps and dicing steps for separatingindividual chips or dies from a wafer are also among the standard steps.

With regard to the structures depicted in FIGS. 1 to 9 b, it may also benoted that these representations are not to scale. For example, thedrawings allow no conclusions to be drawn in terms of verticaldimensions in relation to a main surface, or surface, of a substrate ofthe electronic device comprising the embodiments of the connectingstructures, nor with regard to lateral dimensions of the respectivestructures conclusions in terms of concrete dimensionings ofimplementations of the embodiments. Rather, the reproduction ratiosselected in the figures have been specified with a view to a clearrepresentation and illustration of the embodiments. For example, thefigures allow no conclusions to be drawn in terms of mutual thicknessratios of layers. Similarly, the figures allow no conclusions to bedrawn in terms of characteristic lengths of lateral structures. Forexample, especially small structures, that is, structures typicallyranging below 5 μm, are depicted in a clearly enlarged manner so as todescribe the embodiments.

FIGS. 1, 2 a, 2 b, and 2 c illustrate a first embodiment of a connectingstructure for an electronic device 100. The electronic device 100 isformed on a substrate on a main surface, or surface. The electronicdevice 100 may both be integrated on a chip as an individual deviceafter a dicing step, or may be integrated on the chip along with furtherelectronic devices and/or other components.

In this context, FIG. 1 illustrates a top view of the main surface ofthe substrate of the electronic device 100 comprising a connectingstructure 110 for a first electrode 120 (not illustrated in FIG. 1)which is arranged, within a first trench 130, below the connectingstructure 110 in relation to the main surface of the substrate.

To enhance understanding of the vertical arrangement of the individualstructures, the electric device depicted in FIG. 1 comprising the firstembodiment of a connecting structure is also illustrated in parallelusing FIGS. 2 a, 2 b, and 2 c. Here, FIG. 2 a illustrates a section A-A′through the device 100, said section being drawn in as a horizontalline. Accordingly, FIG. 2 b illustrates a section through the device 100along the line which is designated by the straight line B-B′ in FIG. 1,while FIG. 2 c illustrates a section along the line designated as lineC-C′ in FIG. 1. Here, the markings 140 (arrow) illustrate the surface,or main surface, of the substrate of the electronic device 100.

As was already mentioned above, the connecting structure 110 for thefirst electrode 120 is arranged above the first electrode 120 inrelation to the main surface of the substrate, and includes a metalstructure 150 which includes, in the embodiment of a connectingstructure which is illustrated in FIG. 1, a metallic conductor line 150a and a contacting area, or a bondpad 150 b. The metallic conductor linehere typically has a width, that is, an expansion along the line definedby the straight line A-A′, of typically between 10 μm and 100 μm,whereas the bondpad 150 b is typically configured to be rectangular orsquare, the two side lengths each ranging between 200 μm and 500 μm. Thebondpad 150 b is frequently configured to be square and to have an edgelength of about 300 μm.

The connecting structure, or connection structure, 110 further includesa lower-lying contact structure 160 which is arranged below the metalstructure 150 in relation to the surface of the substrate, and istypically prepared from polymorphous silicon (poly Si), which maypossibly be configured as doped or highly doped polysilicon in order toadapt an electrical resistance of the lower-lying contact structure 160.Alternatively, the contact structure which is arranged lower down mayalso be produced from a metal, for example aluminum (Al), tungsten (W),copper (Cu), gold (Au), silver (Ag), titanium (Ti), or an alloy. Thelower-lying contact structure 160 here is in direct contact with thefirst electrode 120 within the first trench 130.

In the embodiment of a connecting structure for an electronic device100, said embodiment being illustrated in FIGS. 1, 2 a, 2 b, and 2 c,the electronic device 100 further includes an insulating layer 170 whichenables, on the one hand, electrical insulation of the first electrode120 from the layers arranged above it. On the other hand, it furtherserves to planarize, or level, the electronic device prior to depositingthe metal structure 150 having the metallic conductor line 150 a and thebondpad 150 b. As is also illustrated in FIGS. 2 a, 2 b, and 2 c, theinsulating layer 170 here also covers the lower-lying contact structure160 at the side facing the metal structure 150. In order to neverthelessenable an electrically conductive contact between the metal structure150 and the lower-lying contact structure 160, a contact hole 180 hasbeen formed in the insulating layer 170. Depending on the specificimplementation of the electronic device and of the embodiment of theconnecting structure, it may be advisable to additionally introduce afurther metallic or semiconducting, essential vertically runningconnection structure in the region between the metal structure 150 andthe lower-lying contact structure 160. Depending on the specificimplementation, the latter is also referred to as a W plug or as a polyplug, or Si plug, should the connection structure in question be made oftungsten (W) or (doped or highly doped) polysilicon. In the context ofthe present application, essentially vertically running structures andobjects are to mean such structures and objects which form, in a normalof the surface of the substrate, an angle of typically less than 20° ,and less than 5°.

As is also illustrated in FIG. 2 a, a further insulating layer 190,which electrically insulates the respective structures from theunderlying structures, is arranged below the first electrode and belowthe lower-lying contact structure, which is typically also referred toas poly because of the utilization of polymorphous silicon. Both theinsulating layer 170 and the insulating layer 190 may be configured, forexample, as oxide layers, nitride layers, or other electricallyinsulating layers which undermine a parasitic, or undesired, verticaltransport of current to the surface of the substrate between theindividual layers and structures. For this reason, the insulating layers170 and 190 are frequently also referred to as oxide, or oxide layer.

The embodiment, depicted in FIGS. 1 to 2 c, of a connecting structurefor the electronic device 100 further includes a connecting structure210 for a second electrode 220 (not illustrated in FIG. 1) within asecond trench 230.

Like the connecting structure 110 for the first electrode 120, theconnecting structure 210 for the second electrode 220 also includes ametal structure 250 and a lower-lying contact structure 260. Like theconnecting structure 110, the connecting structure 210 may be made of ametal such as aluminum, copper, titanium, tungsten, gold, or silver. Inaddition, like the connecting structure 110, it may also include anyalloy having a specific electric resistance adapted to the purpose ofutilization.

The lower-lying contact structure 260 for the second electrode 220 maybe made of a metal, an alloy, and a semiconductor material, for examplepolymorphous, or polycrystalline, silicon (poly Si). However, unlike themetal structure 150, the metal structure 250 for the second electrode220 is typically dimensioned such that in wide areas of the electronicdevice 100, its surface area exceeds the minimum size necessary forcontacting. More specifically, in the electronic device, depicted inFIGS. 1 to 2 c, comprising the first embodiment of a connectingstructure, the metal structure 250 is deposited on a large part of thearea of the device 100, so that the electrical contacting of the secondelectrode with an exterior circuit may be performed, for example, bymeans of a bonding process in a large area of the surface of theelectric device.

Similar to the first electrode 120 within the first trench 130, thesecond electrode 220 within the second trench 230 is directly connected,via the lower-lying metal structure 260, in an electrically conductivemanner to a region arranged outside the second trench 23. In otherwords, the two electrodes 120, 220 are routed out of the trenches 130,230 through the two lower-lying contact structures 160, 260.

Just like FIG. 2 a has illustrated this for the lower-lying contactstructure 160 of the first electrode, the lower-lying contact structure260 for the second electrode 220 is covered, as is illustrated in FIG. 2b, by the insulating layer 170, except for a contact hole 280, viawhich—possibly via a contact structure which runs in an essentiallyvertical manner (for example, W plug or Si plug)—the lower-lying contactstructure 260 is in electrical contact with the metal structure 250. Inthis manner, the second electrode 220 may be electrically contacted viathe metal structure 250, which also serves as a bondpad, via thelower-lying contact structure 260.

Accordingly, the first electrode 120 may also be connected to anexterior circuit via the bondpad 150 b of the metal structure 150 andthe metallic conductor line 150 a and the lower-lying contact structure160. Here, both the metal structure 250 and the bondpad 150 b aretypically electrically coupled, or connected, to a housing via bondwireswhich are deposited during a bonding process.

As is illustrated in FIG. 1, the first trench 130 is aligned essentiallyin parallel with the first electrode 120, and the second trench 230 isaligned essentially in parallel with the second electrode 220, or theyextend essentially in parallel. For the purposes of the presentapplication, trenches and/or electrodes which run or extend essentiallyin parallel are to mean those which typically form an angle of less than20° and less than 5° with each other. Here, the first electrode 120 andthe second electrode 220 extend toward an edge region 300 of the device100, the first electrode 120 extending farther, on the side of the edgeregion, within the first trench 130 than the second electrode 220 withinthe second trench 230. Typically, the first electrode extends at least10 μm farther toward the edge region 300 than does the first electrode220. Depending on the respective implementation of the electronic device100, the first electrode 120 extends by more than 50 μm or by more than100 μm farther toward the edge region 300 than does the second electrode220.

In addition, the device 100 additionally includes a further edge region310 which is opposite the edge region 300. As is also illustrated inFIG. 1, the second electrode 220 here extends farther toward the furtheredge region than does the second electrode 120. Typically, the secondelectrode 220 extends by at least 10 μm farther toward the further edgeregion 310 than does the first electrode 120. However, depending on therespective implementation, or dimensioning, of the device 100, thesecond electrode 220 may also extend by at least 50 μm or by at least100 μm farther toward the farther edge region 310 than does the firstelectrode 120.

FIG. 2 c illustrates a partial cross-sectional representation of thedevice 100 along the line designated as C-C′ in FIG. 1 and runningthrough the device 100. Here, the first electrode 120 and the secondelectrode 220 are arranged in an electrode plane with regard to the mainsurface, or surface, indicated by the marking 140, of the substrate.

For the purposes of the present application, two electrodes belonging tothe same electrode plane are to mean such electrodes which, with regardto the cross-section which is perpendicular to an extension direction ofthe trenches 130, 230, are given identical or similar geometrical shapeswithin the trenches, and/or which are prepared during the samemanufacturing step(s). This may mean, for example, that the twoelectrodes in question have identical or comparable upper edges andlower edges in relation to the main surface of the substrate. For thepurposes of the present application, identical or comparable upperedges, identical or comparable lower edges, and identical or comparablegeometrical shapes are to mean those which differ from one another bytypically less than +/−30%, and by less than +/−20%.

Depending on the specific implementation of the device 100, it may, inaddition, be advisable or necessary to electrically couple the mesaregion between the two trenches 130, 230 to the metal structure 250.Examples of this are, among others, vertical transistors as will bedescribed in more detail below in the present application. For thispurpose, the insulating layer 170 and the further insulating layer 190may be connected, in the region between the two trenches 130, 230, tothe metal structure 250 through one or several further contact holes320. Depending on the specific implementation of the device 100 and themethods used for manufacturing, it may be advisable in this context toprovide separate contact holes or contact trenches 320 for the twoinsulating layers 170, 190, which contact holes or contact trenches, inturn, are contacted with the metal structure 250 via, for example, a Wplug or an Si plug, depending on the specific implementation of thedevice 100.

Similar to the further embodiments, the above-described embodiment isbased on the findings that, based on an overall surface area of thedevice 100, an increased integration may be achieved in that twodifferent electrodes 120, 220, which are arranged in the same electrodeplane with regard to the main surface of the substrate of the electronicdevice 100, extend over different distances toward the edge-region sideend of the trench wherein they are arranged. In this manner, asubstantial proportion of the overall surface area of the device may beutilized for active, semiconducting structures, the so-called cellfield, without these areas being lost for the contacting of the cellfield due to necessary metallic conductor lines.

Thus, with the embodiment described, as with the further embodiments, inrelation to the overall surface area of the device 100, the integrationdensity may be increased in that the cell field is enlarged, and thespace on the substrate which is necessary for the connecting structuresis restricted. In other words, the embodiments enable reduced spacerequirements for the connecting structures 110, 210, and thus, with agiven overall surface area, an increase in the space for the activecomponents of the electronic device 100, or the cell field.

As further embodiments will illustrate, the embodiments of theconnecting structure for an electronic device 100 additionally enablethe use of several, electrodes, arranged one above the other, within thetrenches. Thus, embodiments enable contacting even so-called high-speeddense trench transistors having an extremely low on-resistance in a veryspace-saving manner.

Thus, so-called “dual-poly transistors” comprising more than onesuperimposed electrode within a trench may be connected in the case ofthe high-speed dense trench transistors.

The embodiment described in the context of FIGS. 1 to 2 c, of aconnecting structure for an electronic device may thus be employed, forexample, for the purposes of DMOS power transistors, wherein animportant goal is the reduction of the specific on-resistance R_(on)·A.In this manner, the static power loss may be minimized, on the one hand,on the other hand, higher current densities may be achieved, as a resultof which smaller and cheaper chips may be used for the same totalcurrent.

In addition, however, it is also necessary, for fast switching, to haveas small a gate charge as possible, for example, with regard to acapacitance between gate and drain. It is true that this frequentlyresults in opposite trends, since measures for reducing the specificon-resistance R_(on)·A will often lead to an increase in the gatecharge. However, the embodiments of the connecting structures describedwithin the context of the present application specifically represent acontribution to a further reduction of the specific on-resistance and tothe implementation of so-called fast-switching dense trench transistors(vertical transistors including densely arranged trenches) having anextremely low on-resistance R_(on)·A.

A possible solution with regard to reducing the specific on-resistanceis to deviate from the planar cell structure, and to use cellscomprising trenches, so-called trench cells, as is also illustrated inFIGS. 1 to 2 c. In this manner, the channel resistance is reduced by aclear increase in the channel width per area. In this case, the metalstructure 250 represents a terminal for a source potential of theelectronic device 100 in the form of the trench transistor, whichfurther includes a drain terminal implemented on a rear of thesubstrate, that is, on the surface which is opposite the surface, ormain surface, of the substrate.

In this manner, an electric resistance between the source terminal andthe drain terminal of the trench transistor is determined to asubstantial degree by the electric resistance of the so-called driftpath (epi resistance), which may be achieved by using deep trenches. Afurther reduction of the drift path resistance may be further reduced,for example, in the entire region of the so-called epi zone, that is, aregion of the trench transistor which was created by epitaxial growth,in that a growing doping is implemented in the entire epi zone.

In addition, the specific on-resistance may be optimized, in thedirection of a low R_(on)·A value, in that so-called dense trenchtransistors are used wherein the trenches are arranged, or packed, sodensely that a location where an avalanche breakdown occurs (avalanchebreakdown location) is shifted, or transferred, to a region of thebottom of the trench.

With regard to a faster switching behavior, a so-called high-speedvariant of a dense trench transistor may be employed wherein the fastswitching is achieved merely in that every other trench, or trenchstrip, is completely applied to the source potential and is thusswitched to be inactive. It is true that this leads to a degradation ofthe specific on-resistance R_(on)·A by about 25-30%, but at the sametime it reduces the gate capacitance and therefore the gate charge by50%, so that the characteristic parameter which is important forfast-switching transistors (FOM=figure of merit),

FOM=R _(on) ·A Q _(Gate) /A,

is reduced overall, that is, in total, by about 10-20 percent, A beingthe surface area of the device, Q_(Gate) being the charge of the gateelectrode, and R_(on) being the specific on-resistance.

Thus, if the electronic device 100 of FIGS. 1 to 2 c is a respectivedense trench transistor, the drain terminal will be localized at therear of the substrate, while the metal structure 250 represents aterminal for the source potential as a second potential, and the metalstructure 150 represents a gate terminal for the gate potential as afirst potential. In this case, the first electrode 120 is the gateelectrode, whereas the second electrode 220 is that electrode arrangedwithin the trench which is switched to be inactive, or switched tosource potential.

It is useful to note at this point that in the case of transistors, thestructure of the further insulating layer 190 inside the trench may beimplemented to be more complex than is illustrated in FIG. 2 c. Forexample, the further insulating layer 190 may include differentthicknesses and/or several layers.

To simplify reference, identical reference numerals will be used, in thefollowing part of the present application, for object, functional units,and structures comprising identical or similar functional properties. Inaddition, summarizing reference numerals shall be used, in the followingpart of the present application, for objects which are includedrepeatedly in one embodiment, unless a single, specific object is to bereferred to. For example, reference numeral 120 shall, on principle,refer to electrodes of the type of the first electrode in the followingpart of the present application.

It is useful in this context to point out that, unless explicitlyindicated otherwise, on the one hand, portions relating to objects andstructures having similar or identical functional properties, and/or toobjects having summarizing reference numerals, are exchangeable amongthe descriptions of the various embodiments. On the other hand, it shallbe noted that a shared use of a summarizing reference numeral or of areference numeral for an object occurring in more than one embodimentshall not imply that these objects include identical features andproperties in the various embodiments or in the embodiment in question,unless explicitly indicated. Utilization of shared or similar referencenumerals shall thus not imply a statement with regard to the specificimplementation dimensioning.

FIGS. 3 and 4 illustrate a further embodiment of a connecting structurefor an electronic device 100 which again may be, for example, ahigh-speed variant of a dense trench transistor. It is only with regardto two aspects that the further embodiment, depicted in FIGS. 3 and 4,of a connecting structure for an electronic device 100 differs from theembodiments illustrated in FIGS. 1 to 2 c and from the electronic device100 depicted there:

1. Unlike the electronic device 100 illustrated in FIG. 1, theelectronic device illustrated in FIG. 3 does not include an individualfirst trench 130 comprising the associated first electrode 120, butincludes a plurality of first trenches 130 comprising associated firstelectrodes 120 (not illustrated in FIG. 3) arranged within the firsttrench 130. Likewise, the electronic device 100 illustrated in FIG. 3further includes a plurality of second trenches 230 comprisingassociated second electrodes 220 (not illustrated in FIG. 3).

2. In addition, the device illustrated in FIG. 3 includes a symmetricalcontinuation, or mirroring, of the electronic device 100 illustrated inFIG. 1 with regard to a mirror axis extending within the region of thefurther edge region 310 and extending perpendicularly to the directionof extension of the trenches 130, 230 through the contact hole 280. InFIG. 3, the respective symmetry axis is drawn in as a dotted line 330.

Because of the “mirroring” of the device 100, several changes occur withregard to the embodiment of the connecting structure which shall bebriefly explained below. Due to the “mirroring”, the electronic device100 illustrated in FIG. 3 additionally includes a plurality of thirdelectrodes 420 (not illustrated in FIG. 3), each arranged within a thirdtrench 430 and also arranged in the same electrode plane with regard tothe first electrodes 120 and the second electrodes 220.

For electrically contacting the third electrode 420, the device 100illustrated in FIG. 3 further includes a connecting structure 410 forthe third electrodes 420 which, again, includes a lower-lying contactstructure 460 and a metal structure 450 in the form of a metallicconductor line, that is, comparable to the metallic conductor line 150a. About an electrical contacting of the third trenches 430 via the deepcontact structure 460, which corresponds to the deep contact structures160, 260 with regard to the choice of material and composition, contactholes 480 are again formed in the insulating layer 170, viawhich—possibly using a W plug or a poly plug—electrical contacting ofthe deep contact structure 460 with the metal structure 450 is enabled.With regard to material composition and dimensioning, the metalstructure 450 essentially corresponds to the metal structure 150, or,more specifically, to the metallic conductor line 150 a. The electrodes120, 220, 420 are thus connected to, or contacted with, the connectingstructures, or the connection structures 110, 210, 410.

The symmetry of the device 100 is interrupted only with regard to theterminal of the metal structure 450. For example, the device 100 furtherincludes a metallic conductor line 490 which connects the metalstructure 450 to the bondpad 150 b in an electrically conductive manner.With regard to the material composition and dimensioning, the metallicconductor line 490 may be similar to the metallic conductor line 150 aand/or the metal structure 450, or may match same.

Due to the “mirroring”, further minor differences result with regard tothe course and the extension of the electrodes 120, 220, 420 and of thetrenches 130, 230, 430. Unlike the embodiment depicted in FIG. 1, in theembodiment illustrated in FIG. 3, the second electrodes 220 now extendconsiderably farther, with regard to the further edge region 310, or thesecond edge region, than the first electrodes 120 in the embodimentillustrated in FIG. 1. While in FIG. 1, the difference is typically atleast 10 μm, in the embodiment illustrated in FIG. 3 it typicallyamounts, in the case of the symmetric layout, to about half the lengthof the entire device along the direction of extension of the trenches.If the dimensions of a device 100 typically range between 1 and 2 mm,the difference of the extension of the second electrode with regard tothe further edge region 310 thus will range, compared to the firstelectrode 120, from about 500 μm to 1000 μm.

Here, the first trenches 130 and the third trenches 430, and/or thefirst electrodes 120 and the fourth electrodes 420, essentially run on astraight connecting line, whereas the second electrodes 220 and/or thesecond trenches 230 run so that they are offset in parallel as comparedto the connecting lines of the first and third electrodes, or trenches.

By contrast, the third electrodes 420 extend at least by 10 μm fartherwith regard to the further edge region 310 as compared to the secondelectrodes 220, typically—depending on the layout of the device 100—by50 μm or at least by 100 μm farther. The embodiment illustrated in FIG.3 of a connecting structure additionally includes a central region 500,into which the first electrodes 120 and the third electrodes 420 do notextend.

FIG. 4 illustrates a cross-section along the line D-D′ illustrated inFIG. 3. Essentially, the cross-section D-D′ differs from thecross-section B-B′ depicted in FIG. 2 b only in that, on the one hand, asymmetrical position with regard to the symmetry line 330 results inFIG. 4 because of the “mirroring” of the device, and in that, unlikesection B-B′ of FIG. 2 b, the trench 230 is not interrupted.

FIGS. 5, 6, 7 a, 7 b, 7 c, 8, 9 a and 9 b depict a further electronicdevice 100 in the form of a dense trench transistor as a high-speedvariant, which is a so-called dual-poly variant, wherein two electrodesare arranged one above the other in two different electrode planeswithin the trenches, of which electrodes the lower one, respectively, isbasically applied to source potential, and wherein in operation theelectrodes which are arranged above the lower electrodes, respectively,are alternately applied to gate potential and source potential.

FIG. 5 illustrates a highly simplified plan view of an electronic device100 in the form of a high-speed variant of a trench transistor, forexample a dense trench transistor. With regard to the architecture, thetrench transistor described in FIGS. 5 to 9 b is similar to theelectronic device 100, described in connection with FIGS. 3 and 4, withregard to the embodiment of the connecting structure. For example, thistrench transistor 100, too, includes a metal structure 150 having ametallic conductor line 150 a, a bondpad 150 b to which the gatepotential of the trench transistor (first potential) may be fed viabondwires, for example. Just as with the device 100 depicted in FIG. 3,the bondpad 150 b here also has a metallic conductor line 490 connectedto it which leads into the metal structure 450 for the third electrodes430 (not illustrated in FIG. 5).

Unlike the device 100 illustrated in FIGS. 3 and 4, in this embodiment aconnecting structure includes the electronic device 100 in the form of atrench transistor comprising a plurality of first, second and thirdelectrodes 120, 220, 420 within respective first, second and thirdtrenches 130, 230, 430, a first trench 130 and a third trench 430, or afirst electrode 120 and a third electrode 420, being again arranged on aconnecting line extending in a straight manner. The second electrodes220, or the second trenches 230, are arranged such that they are offsetthereto in a parallel manner, the first electrodes 120 and the thirdelectrodes 420, again, not extending into the central region 500.Accordingly, the second electrodes 220 extend less far into the edgeregion 300 than the first electrodes 120, and, with regard to thefurther edge region 310, less far than the third electrodes 420 (or therespective trenches 130, 230, 430).

However, the embodiment of a connecting structure which is described inFIGS. 5 to 9 b differs from the above-described devices in two essentialpoints. On the one hand, the contact hole 280 in the central region isimplemented as a continuous contact hole, or as a continuous contactopening. In addition, the trenches 130, 230, 430 have two electrodesarranged therein, respectively, which are arranged one above the other.More specifically, with regard to the main surface of the substrate, afirst lower electrode 120 u is arranged below the first electrode 120, asecond lower electrode 220 u is arranged below the second electrode 220,and a third lower electrode 420 u is arranged below the third electrode420. Details on this will be more fully described with regard to FIG. 7c.

Here, the respective lower electrodes 120 u, 220 u, 420 u are applied tosource potential during the operation of the transistor. For contactingthe respective lower electrodes 120 u, 220 u, 420 u, the embodimentdescribed in FIGS. 5 to 9 b further includes a lower-lying contactstructure 265, 465, referred to as poly S, respectively, which will beexplained in more detail below with reference to FIGS. 6 to 9 b. Also,the device further includes a lower-lying contact structure which isreferred to as poly S 165 and arranged in the region of the metalstructure 150, but is not illustrated in FIG. 5 so as to simplify therepresentation.

As was already described in the context of the preceding embodiments,the lower-lying contact structures 160 (not illustrated in FIGS. 5), 260and 460 serve for contacting the first, second and third electrodes 120,220, 420, which, in the event of the non-high-speed variant of a trenchtransistor, are applied to gate potential during the operation of thetransistor, and are therefore referred to as poly G 160, 260, 460because of their implementation on the basis of polymorphous silicon(poly Si). In the high-speed variant illustrated in FIGS. 5 to 9 b, thesecond electrodes 220, which otherwise serve as gate electrodes, arealso applied to source potential during operation. Here, the electrodes220 which are applied to source potential form a regular arrangement inrelation to the electrodes 120, 420 which are applied to gate potential.

In the electronic device 100 depicted in FIGS. 5 to 9 b, every otherelectrode, which actually acts as a gate electrode, is electricallycoupled to the terminal for the source potential. More specifically, thefirst electrodes 120 and the third electrodes 420 are connected to thegate potential via the respective connecting structures duringoperation, whereas the second electrodes 220 are connected to theterminal for the source potential, so that they are also applied tosource potential during operation. Irrespective thereof, however, it iseven in the case of the high-speed variant that the respectivelower-lying contact structures for the second electrodes 220, which areapplied to source potential during operation, are referred to as “polyG”.

In addition, the metallic conductor line 150 a forms, along with themetallic conductor line 490 and the metal structure 450, the so-calledgate runner, which enables, as a U-shaped metallic structure, theconnection of the first electrode 120 and of the third electrode 420within the first trench 130 and the third trench 430. For contacting atan external circuit or the housing of the electric device 100, the gaterunner thus typically also includes a bondpad 150 b.

The embodiment of a connecting structure which is illustrated in FIGS. 5to 9 b thus enables, in the case of trench transistors having severalpoly electrodes 120, 220, 420, 120 u, 220 u, 420 u, the terminals to beimplemented for those polyelectrodes which are applied to sourcepotential in operation and are located within the trench 130, 230, 430,respectively, by means of a so-called source finger structure below themetal structure, or source cell field metallization 250, not illustratedin FIG. 5. As a further simplification, there is the possibility—in thecase of the high-speed variant illustrated in FIGS. 5 to 9 b—of routingthrough only those trenches 230 below the source finger structure, andto contact them with the source finger structure, which are to be fullyapplied to source potential during operation and thus are inactive interms of a current between the source contact and the drain contact(forward current).

Here, the source finger structure includes, the lower-lying contactstructures poly G 260 and poly S 265, arranged in the central region 500of the electronic device, along with the associated structures.

Compared to a known solution having two interlocking metallizationrunners, more specifically a gate runner, which is also depicted in FIG.5, and an additional so-called source metal ring, the principle of usingthe source finger structure enables, within the context of embodimentsof a connecting structure, a significant saving in terms of the spacenecessary for contacting. Compared to a classical structure inaccordance with a possible solution laid out above which connects thetwo poly S—which are successively routed out of the trench at the chipedge—in the chip edge region, and therefore leads to a considerablespace requirement in chip edge design, one embodiment of a connectingstructure enables considerable space saving.

The structure illustrated in FIG. 5, for example, of an embodiment of aconnecting structure thus enables the contacting of the sourceelectrodes (second electrode 220, second lower electrode 220 u) withinthe trench 230 in the center of the chip (central region 500) by meansof the source finger structure below the source metal of the metalstructure 250. Due to the introduction of the source finger structure,the large space requirement at the chip edge, which is due to thetypical rules for laying out a design having a sufficiently high yield(metal design rules), is reduced. For example, the embodiments of aconnecting structure as is illustrated, for example, in FIGS. 5 to 9 benable, that only the gate electrodes (first electrode 120, thirdelectrode 420) within the trenches 130, 430 are now connected at thechip edge.

FIG. 5 illustrates an overview of a chip having the described high-speedvariant, wherein only the gate runner is routed at the chip edge region,whereas the source finger structure described is arranged in the centerof the chip (central region 500). In other words, FIG. 5 illustratesthat regular trenches, or their electrodes 120, 420, which are to beapplied to gate potential during operation, are connected from the chipedge via the gate runner described. As will also be illustrated by FIGS.6 to 9 b, it is there that classically the poly G 460 or the gate polyis contacted with the gate runner, so that same may be applied to gatepotential during operation. The poly S 165, 465, or the source poly isconnected to the metal structure 250 in the process, so that it may beapplied to source potential during operation. The trenches which arefully applied to source potential during operation, or their electrodes(second electrode 220 and second lower electrode 220 u) are cut off fromchip-edge contacting by their smaller extension with regard to the edgeregion 300. Likewise, the second electrode 220 and the second lowerelectrode 220 u are cut off, due to their smaller extension with regardto the further edge region 310, also with regard to the connectingstructure 410 for the electrodes 420, 420 u of the third trenches 430.To make up for this, however, they are fully routed through below thesource finger construction in the center of the chip, that is, in thecentral region 500, and are contacted there, whereas the electrodes 120,120 u, 420, 420 u of the first trenches 130 and of the third trenches430 do not extend into the central region 500.

In the center of the chip, that is, in the region of the central region500, the two polys, the poly G 260 and the poly S 265, are connected tothe metal structure 250, so that they may be applied to source potentialduring operation. For example, the poly G 260—which in the “regularcase”, that is, in the case of a transistor which is not implemented asa high-speed variant would be contacted with the terminal for the gatepotential—is connected to the metal structure 250, that is, to theterminal for the source potential.

Below, the structure, depicted by the rough overview in FIG. 5, of theelectronic device and of the embodiment of the connecting structureshall be explained in more detail. For this purpose, a first region 510in the region of a corner of the electronic device 100 shall beinitially described in more detail in connection with FIGS. 6, 7 a, 7 b,and 7 c, whereafter a second region 520 in the region of the center ofthe device 100 shall be described in connection with FIGS. 8, 9 a and 9b.

FIG. 6 illustrates the first region 510 of FIG. 5 as an enlargedrepresentation, that is, is zoomed in on the chip corner of thehigh-speed variant of the trench transistor 100. FIGS. 7 a, 7 b, and 7 ceach illustrate a section through the trench transistor along one of thethree lines illustrated as A-A′, B-B′ and C-C′ in FIG. 6, FIG. 7 aillustrating a section starting in the third trench 430, FIG. 7 billustrating a section starting in a second trench 230, and FIG. 7 cillustrating a section which is perpendicular to the direction of theextension of the second trench 230 and of the third trench 430 throughthe actual cell field of the transistor.

In this context, the sections in FIGS. 7 a, 7 b, and 7 c differ from thesections illustrated in FIGS. 2 a, 2 b, and 2 c in that, with regard tothe layer sequence, the trench transistor of FIGS. 5 to 9 b in each ofthe trenches 130, 230, 430 includes two electrodes, more specificallythe first electrode 120, the second electrode 220, and the thirdelectrode 420, which are arranged within the same electrode plane withregard to the main surface of the substrate, and includes the firstlower electrode 120 u, the second lower electrode 220 u, and the thirdlower electrode 420 u, which are also arranged on a common electrodeplane with regard to the main surface of the substrate, the twoelectrode planes of the electrodes 120, 220, 420, and of the electrodes120 u, 220 u, 420 u not being the same electrode planes, however.

In order to impede any undesired electrical contact between the upperelectrode 120, 220, 420, respectively, with the lower electrode 120 u,220 u, 420 u, respectively, within the same trench 130, 230, 430,insulating layers are inserted between the two electrodes of a trench ineach case, which may be oxide layers or nitride layers, for example.Thus, more specifically, the insulating layer 120 i is arranged betweenthe first electrode 120 and the first lower electrode 120 u, theinsulating layer 220 i is arranged between the second electrode 220 andthe second lower electrode 220 u, and the insulating layer 420 i isarranged between the third electrode 420 and the third lower electrode420 u.

This is illustrated, for example, by the section along line C-C′depicted in FIG. 7 c. As was already the case in the context of FIG. 2c, here, too, there is a further contact opening 320 in the region ofthe mesa between the two trenches 230, 430, which—possibly by using a Wplug or a poly plug—enables contacting of the semiconductor with themetal structure 250 in the area of the mesa. Because of its use as acontacting area, or bondpad, for the source terminal of the transistor,the metal structure 250 is also referred to as a source metal. Tosimplify the representation of the section 7 c, details with regard tothe doping, the implantation and the doping profile of the respectivedoping in the region of the mesa are also not illustrated. As wasalready illustrated in the context of FIG. 2 c, the further insulatinglayer 190, which covers the bottoms of trenches 230, 430 in FIG. 7 c andwhich is also arranged on the main surface of the substrate outside thetrenches 230, 430, may absolutely differ, within the trench itself, withregard to thickness and/or composition, both within the trench itself,from trench to trench, and from trench to the main surface of thesubstrate.

Only for the purposes of simplifying the representation, a single,identical insulating layer 190 is illustrated here. In addition, withinthe trench, the further insulating layer may also be removed and/or besupplemented or replaced by a further layer or layer sequence.

In addition, in FIG. 7 c, the potential during operation of thetransistor is schematically drawn into the four electrodes 220, 220 u,420, 420 u in the form of the designations “S” and “G”. As was explainedabove, the lower electrodes 220 u, 420 u are basically connected to thesource potential within the context of the embodiment illustrated inFIGS. 5 to 9 b, whereas it is only the second electrode 220 of the upperelectrodes that is also connected to the source potential duringoperation (“S”). The first electrode (not illustrated in FIG. 7 c) andthe third electrode 420, by contrast, are connected to the gatepotential during operation (“G”).

In this context, it is also useful to mention that the representationselected in FIG. 7 c is to be understood as a schematicalrepresentation. For example, with electrodes arranged on top of oneanother within a trench and which are separated from one another by aninsulating layer which is thin compared to the thickness of theelectrodes, there may quite possibly be a (partial) transfer of thetopology of the trenches to the electrodes. It may happen, for example,that the electrodes are both U-shaped, it being quite possible for theelectrodes within the trench to overlap with regard to a plane inparallel with the main surface of the substrate.

As was already mentioned, FIG. 7 a illustrates the section along thestraight line A-A′ along the extension direction of the third trench430. As was also illustrated by FIG. 7 c, the third electrode 420 hereis routed out of the trench 430 via the poly G 460, and is connected tothe gate runner, or the metal structure, 450 via the contact hole 180 inthe insulating layer 170—possibly via a W plug or a poly plug. The thirdlower electrode 420 u, which is to be apply to source potential duringoperation, is routed out of the trench 430 via the poly S 465, and isconnected to the metal structure, or the source metal, 250 via a recess,or hole, 520 in the poly G 460, and via a further contact hole 530 inthe insulating layer 170. Here, the poly G 460 is separated from thepoly S 465 by an insulating layer 470 which extends into the region ofthe trench 430 and is continued there as the insulating layer 420 i.

Due to the different extensions of the electrodes 220, 220 u incomparison with the extensions of the electrodes 420, 420 u, the secondelectrode 220 and the second lower electrode 220 u are not connected tothe poly G 460 and the poly S 465, respectively, as is illustrated inFIG. 7 b. In the section depicted in FIG. 7 b, both the poly G 460 andthe poly S 465 are separated from the second electrode 220 and thesecond lower electrode 220 u by the insulating layer 470, on the onehand, and by the insulating layer 170. Due to the oblong shape of thecontact hole 180 within the insulating layer, and due to the extensionof the contact hole 530 within the insulating layer 470, it is even inthe region of the section illustrated in FIG. 7 b that the gate runneris electrically connected to the poly G 460, and the source metal 250 iselectrically connected to the poly S 465.

FIG. 8 illustrates the second region 520 of FIG. 5 as an enlargedstructure. More specifically, FIG. 8 zooms in on the source fingercontact structure in the center of the chip, where the metallicconductor line 490 of the gate runner runs past.

In addition, FIG. 8 illustrates that the first trenches 130 and thethird trenches 430 do not extend as far as into the central region 500,but are arranged on a straight connecting line, as is illustrated, forexample, by the lines designated by A-A′ in FIG. 8, which at the sametime mark the cross-section, depicted in FIG. 9 a, of the trenchtransistor 100. The line in FIG. 8 which is marked as B-B′ extendswithin the second trench 230 and illustrates the cross-section,illustrated in FIG. 9 b, of the trench transistor 100. Here, the sectiondepicted in FIG. 9 b runs through the second trench 230, as is alsoillustrated by the connecting line B-B′.

In addition, FIG. 8 schematically illustrates the arrangement and theextension of the poly S 265 and that of the poly G 260 directly in thecentral region 500 along with the contact hole 280. Here, the poly G 260includes a recess 530, also referred to as opening or hole in the poly G260 and serving for contacting the second lower electrode 220 u with thesource metal, or with the metal structure, 250, as will be explainedlater on in the context of FIG. 9 b.

FIG. 8 further illustrates that the trenches 230 which are fully appliedto source potential in operation, or their electrodes 220, 220 u arerouted through below the source finger structure in the center of thechip and are contacted in this area. Both polys (poly S 265 and poly G260), by means of which the second lower electrode 220 u and the secondelectrode 220 are lifted above the main surface, or surface, of thesubstrate, and/or are routed out for contacting purposes, are connected,in the central region 500, to the metal structure 250, so that both maybe applied to source or to source potential in operation. In thismanner, the poly, which in the “regular case” (non-high-speed variant ofthe trench transistor) is applied to the gate potential in operation, isapplied to source potential.

FIG. 9 a, which depicts a cross-section of the trench transistor 100starting in the region of the first trench 130 and ending in the regionof the third trench 430, illustrates, on the basis of the layer sequenceillustrated there, that the two upper electrodes 120, 420 and the twolower electrodes 120 u, 420 u of the two trenches 130, 430 are notconnected to the poly G 260 and the poly S 265, and that both the firsttrench 130 with its two electrodes 120, 120 u and the third trench 430with its two electrodes 420, 420 u do not extend into the central region500.

In addition, FIG. 9 a illustrates that the poly S 265 is electricallyinsulated from the poly G 260 by the insulating layer 470 and iscontacted—possibly via a W plug or a poly plug—to the source metal 250above the surface of the substrate, which is marked by the two arrows140 (Si OF) in FIG. 9 a and FIG. 9 b, via the contact hole 280 in FIG. 9b. In operation, the poly G 260 in the central region 500 may be appliedto source potential via the contact hole 280 in FIG. 9 a and the sourcemetal 250, or the metal structure 250, as is also noted in FIG. 8.

FIG. 9 b illustrates a cross-section of the electric device 100 alongthe connecting line B-B′ which is illustrated in FIG. 8 and extendsfully within the second trench 230, which extends through the centralregion 500, unlike the first trench and the third trench 430. FIG. 9 bfurther illustrates that the second electrode 220 is routed out by meansof the poly G 260 via the surface of the substrate (cf. marking 140),and is contacted with same. Since, as FIG. 9 a has already illustrated,the poly G 260 is in connection with the source metal 250 through thecontact hole 280 in the insulating layer 170, the second electrode isthus contacted due to the extension of the poly G 260 in the plane,which is illustrated in FIG. 8. In addition, the poly G 260 iselectrically insulated, by the insulating layer 170, from the sourcemetal 250 at least in the region of the cross-section illustrated inFIG. 9 b.

As was already explained in connection with FIG. 8, the poly G 260includes the recess 530 which eventually also enables contacting of thepoly S 265 with the source metal 250 via the contact hole 280 in theinsulating layer 170, and possibly via a W plug or an Si plug. In thismanner, the poly S 265 may also be connected, in operation, to thesource potential via the source metal, or the metal structure, 250. Thepoly S 265 here is in direct contact with the second lower electrode 220u, so that this electrode may be applied to the source potential duringthe operation of the transistor 100, as was already illustrated in FIG.7 c.

On principle, of course, in a further embodiment there is thepossibility of contacting all poly S structures within the centralregion 500 of the electric device, of a trench transistor. In this case,it may be advisable to actually not have the first and possibly thethird electrodes within the first and possibly the third trenches extendas far as into the central region, but there is the possibility ofhaving at least the lower electrodes, respectively, of the possibly twotrenches extend into the central region, possibly within the respectivetrenches, so that they may be directly contacted there in the centralregion.

The embodiment, depicted in FIGS. 5 to 9 b, of a connecting structure inthe event of a trench transistor 100 as an electric device thusillustrates the flexibility and possible space saving by saving a sourcemetal ring in the event of the fast-switching high-speed variant in thecase of a trench transistor. This embodiment thus illustrates how thetrenches 230, which are applied to source potential during subsequentoperation, with their electrodes 220, 220 u are routed through, whiletrenches which are not applied to source are not routed through belowthe source finger structure in the region of the center of the chip atthe same time. These trenches, more specifically the first trench 130and the third trench 430, are also referred to as gate trenches, sincethey include at least one electrode, namely the first electrode 130 andthe third electrode 430, respectively, which may be applied to gatepotential in normal operation. These are interrupted, before the sourcefinger structure, that is, do not extend as far as into the regionthereof These trenches, or their electrodes, are contacted from furtheroutside, that is, for example from the chip edge. The embodimentillustrated in FIGS. 5 to 9 b thus illustrates a trench structure whichis interlocking in a comb-type manner and includes a patterned sourcefinger contact structure having source finger and high-speed terminals.

Such an embodiment of a connecting structure may be employed, forexample, in the case of trench transistors for smaller source/drainvoltages (up to about 15 V), in the range of medium voltages (about 10 Vto about 120 V), and in the range of higher voltages (above 100 V).Embodiments of a connecting structure thus enable trench transistors tobe contacted, in a space-saving manner, with two or several electrodeswithin the trench, at least one electrode of which is to be applied tosource potential in subsequent operation. By introducing the resultingsource finger structure below the cell-field source metal, a contactingmay be achieved which is space-saving, thus improves the specificon-resistance (R_(on)), and contacts at least one source electrodewithin the trench.

In the context of the present application, the metallic structures whichare also provided for connecting the electric device to outer circuits,or to their housing, have been described, depicted and discussed, withinthe context of the embodiments described here, almost exclusively asrectangular structures, or as polygonal structures comprising angles of90° in each case. Evidently, this does not represent any limitation withregard to the lower-lying contact structures or other structures, andonly serves to simplify the figures and make them clearer.

For example, any polygonal structures which even have angles whichdeviate from 90° are not only feasible, but are actually employed.

With embodiments of connecting structures, the first electrode at anedge region side end of the first trench extends, for example, by adistance farther to the edge region of the electronic device than thesecond electrode, the distance being larger than or equal to 10 μm.

Likewise, the second electrode extends, with regard to a further edgeregion opposite the edge region, by a further distance farther to thefurther edge region than does the first electrode, the further distancebeing larger than or equal to 10 μm.

With embodiments of a connecting structure, wherein the connectionstructure for the first potential and/or the connection structure forthe second potential include(s) an electrically conductive contactstructure extending vertically to the main surface of the substrate, thecontact structure includes a metal or a semiconducting material. In thiscase, in embodiments of a connecting structure, the contact structuremay include, for example, tungsten or doped polycrystalline silicon.

The connection structure of embodiments of a connecting structure forthe first potential and/or the connection structure for the secondpotential additionally include(s) contacting areas, or bondpads. Thecontacting areas here include a metal.

In the case of embodiments of a connecting structure which include aplurality of first trenches having first electrodes associatedrespectively, and/or a plurality of second trenches having secondelectrodes associated respectively, the plurality of first trenches andthe second trench, the plurality of first trenches and the plurality ofsecond trenches, or the first trench and the plurality of secondtrenches are arranged in a regular manner. With embodiments ofconnecting structures comprising first, second, and third trenches, afirst edge region and a second edge region, a central region, a firstelectrode within the first trench, a second electrode within the secondtrench, and a third electrode within the third trench, which arearranged in an electrode plane arranged with regard to a main surface ofa substrate of the electronic device, and wherein the embodiments of theconnecting structures include a plurality of first trenches having firstelectrodes associated respectively, and a plurality of third trencheshaving third electrodes associated respectively, and/or wherein theembodiments include a plurality of second trenches of the secondelectrodes associated respectively, the first trenches, second trenches,and third trenches are arranged in a regular manner.

Within the context of the present application, objects, such asstructures, trenches, electrodes, metallizations, edges and edgeregions, which are essentially opposite one another, are understood tomean those which are opposite both in a parallel manner and which alsoform a specific angle toward one another with regard to an direction,for example in the form of an orientation, characteristic direction oralignment. In addition, essentially opposite objects are also understoodto mean those whose connecting line forms any angle desired with theobjects concerned, or their advantageous directions.

For example, essentially opposite edges and essentially opposite edgeregions are not only understood to mean those which are opposite inparallel or are aligned in parallel and are opposite if they form anangle of 0° with one another with regard to their alignment(advantageous direction), and have, with regard to their connectingline, an angle of 90° with same in each case.

In some embodiments, for example, devices may include edges and edgeregions which have angles ranging from 0° to 90° with each otherregarding an advantageous direction, alignment or other characteristicdirection. It shall be noted in this context that in the event thatobjects have an angle of more than 90°, but less than 180° with eachother, they will also have an angle of 0° and 90° with each otherbecause of the prevailing geometric conditions and the continuability ofthe (imagined) lines.

For example, such edges, structures or edge regions which are arrangedperpendicularly to one another with regard to their orientation, thatis, for example along two perpendicularly superimposed edges of a die ora chip, are also essentially opposite. In this case, the connecting linebetween these objects with their characteristic alignments forms anangle of 45°, for example, in each case.

In further embodiments, the devices include edges and edge regions whichare not implemented as straight lines but are implemented to be bent orcurved. Examples of such devices are round, circular or oval edgeregions or edges of a device, which are implemented on a wafer, forexample. In this case, the above explanations with regard to theorientation, the characteristic alignment or the advantageous directionare to be understood in the local sense in terms of a tangent on thecurved edges, edge regions, structures or objects.

For example, only one single radially designed device having a center ora central point of the device may be arranged on a round substrate orwafer. These embodiments, too, have mutually opposite edge regions whichlocally, in terms of a tangent, have an angle of 0° with regard to aconnecting line through the center, or the midpoint, of the wafer inquestion.

Also with regard to straight connecting lines, or connecting linesrunning essentially straight, or essentially straight connecting lines,such a connecting line is understood to mean a connecting line, withinthe context of the present application, which extends not only in termsof a (mathematical) straight line, but may also run steadily also in theform of a bent line, in the mathematical sense. In some embodiments, forexample, electrodes and/or trenches may thus also be arranged onmeander-shaped connecting lines, spiral-shaped connecting lines, orother curved connecting lines.

In embodiments of a connecting structure for a device having a curvatureor a bent edge or edge region at least on one side of the substrate,that is, for example, round substrates or wafers, the first trench andthe second trench, or the first trenches and the second trenches, forexample, each comprising their associated electrodes, may not only runin parallel. For example, with embodiments of a connecting structure ofa round or oval device, the first trench and the second trench, or thefirst trenches and the second trenches, in each case along with theirassociated electrodes, may run toward a central point, for example themidpoint of the device. In this case, the first trenches and the secondtrenches no longer run in parallel, but form an angle also with regardto their orientations. In other embodiments of connecting structures fordevices, the respective trenches and the associated electrodes maypossibly also be arranged on arch-shaped lines.

In the event of an embodiment of a round device, for example, also thefirst trench and the third trench, or the first trenches and the thirdtrenches, may be arranged on a wafer such that the essentially straightconnecting lines of the respective trenches and electrodes no longer runin parallel, but run toward a common central point. In this case theythus form an angle with one other.

While this invention has been described in terms of several embodiments,there are alterations, permutations, and equivalents which fall withinthe scope of this invention. It should also be noted that there are manyalternative ways of implementing the methods and compositions of thepresent invention. It is therefore intended that the following appendedclaims be interpreted as including all such alterations, permutationsand equivalents as fall within the true spirit and scope of the presentinvention.

1. A semiconductor device including a connecting structure comprising:an edge region; a first trench and a second trench running toward theedge region; a first electrode within the first trench; and a secondelectrode within the second trench; wherein the first and secondelectrodes are arranged in a same electrode plane with regard to a mainsurface of a substrate of the electronic device within the trenches;wherein the first electrode extends, at an edge region side end of thefirst trench, farther toward the edge region than the second electrodeextends, at an edge region side end of the second trench, toward theedge region; and wherein the first electrode is connected to aconnection structure for a first potential, and the second electrode isconnected to a connection structure for a second potential.
 2. Thesemiconductor device of claim 1, wherein the connection structure forthe first potential contacts the first electrode in a region whichextends further to the edge region.
 3. The semiconductor device of claim1, wherein the first trench extends farther toward the edge region thando/does the second electrode and/or the second trench.
 4. Thesemiconductor device of claim 1, further comprising a further edgeregion which is essentially opposite the edge region, and wherein thesecond electrode, at an end of the second trench which is facing thefurther edge region, extends farther toward the further edge region thanthe first electrode extends, at an end of the first trench which isfacing the further edge region, toward the further edge region.
 5. Thesemiconductor device of claim 4, wherein the connection structure forthe second potential contacts the second electrode within a region whichextends farther toward the further edge region.
 6. The semiconductordevice of claim 4, wherein the second trench extends farther toward thefurther edge region than do/does the first electrode and/or the firsttrench.
 7. The semiconductor device of claim 1, wherein the firstelectrode and/or the second electrode extend(s) beyond the region of thefirst trench and of the second trench, respectively.
 8. Thesemiconductor device of claim 1, wherein the connection structure forthe first potential and/or the connection structure for the secondpotential comprise(s) an electrically conductive contact structureextending vertically to the main surface of the substrate.
 9. Thesemiconductor device of claim 1, wherein the first trench furthercomprises a first lower electrode arranged below the first electrode inrelation to the main surface of the substrate, the first electrode andthe first lower electrode being arranged on two electrode planes withinthe first trench, and wherein the connection structure for the firstpotential and/or the connection structure for the second potentialcomprise(s) a contact structure for contacting the first lowerelectrode.
 10. The semiconductor device of claim 1, wherein the secondtrench further comprises a second lower electrode arranged below thesecond electrode in relation to the main surface of the substrate, thesecond electrode and the second lower electrode being arranged on twoelectrode planes within the second trench and wherein the connectionstructure for the first potential and/or the connection structure forthe second potential comprise(s) a contact structure for contacting thesecond lower electrode.
 11. The semiconductor device of claim 1, furthercomprising: a further edge region of the electronic device, which isessentially opposite the edge region; a third trench running toward theedge region and the further edge region; a third electrode within thethird trench, which extends farther toward the further edge region thando the first electrode and the second electrode; and a central region ofthe electronic device, into which the first and third electrodes do notextend; the first, the second, and the third electrodes being arrangedin the same electrode plane with regard to the main surface of thesubstrate of the electric device within the trenches; and the thirdelectrode being connected to a further connection structure for anelectrical potential.
 12. The semiconductor device of claim 11, whereinthe first electrode and the third electrode run on an essentiallystraight connecting line.
 13. The semiconductor device of claim 11,wherein the further connection structure is electrically conductivelyconnected to the connection structure for the first potential.
 14. Thesemiconductor device of claim 11, wherein the third trench furthercomprises a third lower electrode arranged below the third electrode inrelation to the main surface of the substrate, the third electrode andthe third lower electrode being arranged on two electrode planes withinthe third trench, and wherein at least one connection structure of theconnection structure for the first potential, of the connectionstructure for the second potential, or the further connection structurecomprises a contact structure for contacting the third lower electrode.15. The semiconductor device of claim 1 further comprising a pluralityof first trenches having first electrodes associated respectively,and/or a plurality of second trenches having second electrodesassociated respectively, and wherein a first trench is arranged betweentwo second trenches, and/or a second trench is arranged between twofirst trenches.
 16. The semiconductor device of claim 1, wherein theelectronic device is a vertical transistor, the first electrode being agate electrode, and the second electrode being a source electrode, andwherein the external structure of the electronic device is a terminalfor the gate electrode.
 17. A connecting structure for an electronicdevice, comprising: an edge region; a first trench and a second trenchrunning toward the edge region; a first electrode within the firsttrench, no further electrode being arranged, to the side of the firstelectrode, within the first trench; and a second electrode within thesecond trench, no further electrode being arranged, to the side of thesecond electrode, within the second trench, wherein the first electrode,at an edge region side end of the first trench, extends farther towardthe edge region than the second electrode at an edge region side end ofthe second trench extends towards the edge region; and wherein the firstelectrode is connected to a connection structure for a first potential,and the second electrode is connected to a connection structure for asecond potential.